It sends my co-workers outside until it's determined that it's safe to go back in.
The alarm went off this time because there was a significant water pressure drop. That causes it to go off since a lack of water pressure wouldn't be helpful if there was a real fire. The sprinkler systems wouldn't work effectively.
A candid shot under a satellite dish while they huddled for shade in the 100 degree weather:
 |
| It's too hot for a fire |